My research objectives are directed toward the study of biochemical catalysis. At present my major interest is to obtain a more complete understanding of the role of metal ion activators in the mechanisms of enzyme catalyzed hydration-dehydration reactions. Specifically, I hope to elucidate, in detailed fashion, the role of metal ion activators in the mechanism of phosphoenolpyruvate hydratase (enolase) action. To achieve this I plan to continue the multipronged approach employed during the current grant period wherein information derived from kinetic and equilibrium binding measurements was augmented by studies of metal binding to enolase using nuclear magnetic resonance techniques. A portion of the planned effort will be to measure rates of association and dissociation of metal ion activators and enolase as part of an attempt to determine what factors contribute to the difference in activating capacities of the various metal ion activators. At present, our understanding of the metal ion activation of yeast enolase is extensive but not complete. Once a clear picture of the role of metal ions in yeast enolase catalysis is obtained, similar detailed studies will be made on other enolases, several of which, while catalyzing the same reaction, are structurally quite different from the yeast enzyme.